package com.cmall.common.foundation.util;

import java.security.MessageDigest;

public class MD5Util {

	private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

	private static final String encryModel="MD5";

	private static String byteArrayToHexString(byte b[]) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++)
			resultSb.append(byteToHexString(b[i]));

		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n += 256;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String MD5Encode(String origin) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			resultString = byteArrayToHexString(md.digest(resultString
						.getBytes()));
		} catch (Exception exception) {
		}
		return resultString;
	}


	/**
	 * 32λmd5.
	 * @param str
	 * @return
	 */
	public  static String md5(String str) {
		return encrypt(encryModel, str);
//    	  return md5encrypt(str);
	}

	/**
	 * md5加密
	 * 方法描述：
	 * 修改备注：
	 * @version 1.0
	 * @param algorithm
	 * @param str
	 * @return
	 * 返回类型
	 */
	public static String encrypt(String algorithm, String str) {
		try {
			MessageDigest md = MessageDigest.getInstance(algorithm);
			md.update(str.getBytes());
			StringBuffer sb = new StringBuffer();
			byte[] bytes = md.digest();
			for (int i = 0; i < bytes.length; i++) {
				int b = bytes[i] & 0xFF;
				if (b < 0x10) {
					sb.append('0');
				}
				sb.append(Integer.toHexString(b));
			}
			return sb.toString();
		} catch (Exception e) {
			return "";
		}
	}

	/**
	 * 可解密的md5加密
	 * 方法描述：
	 * 修改备注：
	 * @version 1.0
	 * @param str
	 * @return
	 * 返回类型
	 */
	public static String md5encrypt(String str) {

		char[] a = str.toCharArray();
		for (int i = 0; i < a.length; i++) {
			a[i] = (char) (a[i] ^ 't');
		}
		String md5 = new String(a);

		return md5;

	}

	/**
	 * md5解密
	 * 方法描述：
	 * 修改备注：
	 * @version 1.0
	 * @param str
	 * @return
	 * 返回类型
	 */
	public static String convertMD5(String str) {

		char[] a = str.toCharArray();
		for (int i = 0; i < a.length; i++){
			a[i] = (char) (a[i] ^ 't');
		}
		String s = new String(a);
		return s;
	}

}
